Braided covered flexible corrugated conduit



Oct. 18, 1966 R. B. WADDELL, JR 3,279,502

BRAIDED COVERED FLEXIBLE CORRUGATED CONDUIT Original Filed April 17,1962 I 5 Sheets-Sheet l INVENTOR. RUSSELL B. WADDELL JR.

Maw/aw ATTORNEY Oct. 18, 1966 R. B. WADDELL, JR 3,279,502

BRAIDED COVERED FLEXIBLE CORRUGATED CONDUIT Original Filed April 17,1962 5 Sheets-Sheet 2 INVENTOR. RUSSELL B. WADDELL JR.

AT TORN EY Oct. 18, 1966 R. B. WADDELL, JR

BRAIDED COVERED FLEXIBLE CORRUGATED CONDUIT 5 Sheets-Sheet 5 OriginalFiled April 17, .1962

FIG-6 Quill INVENTOR. RUSSELL B. WADDELL JR.

MW Mae/L ATTORNEY United States Patent 3,279,502 BRAIDED COVEREDFLEXIBLE CORRUGATED CONDUIT Russell B. Waddel], Jr., Chesterland, Ohio,assignor to Dayco Corporation, Dayton, Ohio, a corporation of OhioContinuation of application Ser. No. 188,042, Apr. 17, 1962. Thisapplication Feb. 23, 1965, Ser. No. 440,343 7 Claims. (Cl. 138122) Thisis a continuation of application Serial No. 188,- 042, filed April 17,1962, now abandoned.

This invention relates to flexible conduit, and particularly to conduitused for the transfer of fluids such as used in vacuum cleaners, hairdryers, oxygen and respirating devices, automotive cooling systems, andthe like. More specifically, the present invention relates generally toflexible conduit of the type having a corrugated tubular body withinternal helical reinforcing coils such as described in United StatesPatents Nos. 2,782,803; 2,766,- 806; 2,822,857, and 2,949,133, all ofcommon assignment with the present application.

Flexible conduits of the type described in the abovementioned patentsare usually manufactured of elastomeric materials, such as rubber orvarious plastics, and are light, flexible, impervious to penetration ofthe fluids being transmitted, and pleasing to the eye. At the same time,such hose are capable of use even though subjected to critical bendingand stretching forces during use. Certain of the prior art conduit hasutilized various unifying means by which the inner reinforcing coils arebonded to the outer members that form the main body of the conduit, suchas heat or adhesive. In addition, certain prior art devices, such asillustrated by United States Patent No. 2,897,840, utilize an enclosedmold and heat and pressure to provide the completed unit. Anothermethod, illustrated in United States Patent No. 2,430,- 081, utilizes acording process to provide corrugations, followed by a vulcanizing step.All these prior art devices have their uses and the methods employedhave proved successful. However, it has long been desired to provide asimpler unifying means of manufacturing conduit to eliminate some or allof these steps; namely, heating, cording, adhesive bonding, or molding,to reduce the cost of mnaufacture and provide other inherent advantages.Such a product and method are descried in the present application inwhich the unifying means is provided by an outer fabric member which isformed in .place, as by braiding, to surmount the entire reinforcingcoil and elastomeric assembly. The resultant unit has all the desirableproperties sought in flexible conduit.

While prior art devices have suggested the use of outer fabric' members,such members were not used as suggested in the present application. Forexample, in the United States Patent Nos. 2,396,059; 2,430,081, and2,897,840 the inventor has suggested the use of a knitted stockinet,designated as a stretchable open mesh fabric for stiffening purposes. InUnited States Patent No. 2,913,011 strips of fabric tape have also beenprovided for such a purpose. In United States Patents Nos. 2,754,- 848and 2,788,804 the use of lock knit open mesh stretchable meinbers issuggested. While braiding has been used in conjunction with those as inUnited States Patent No. 2,918,777, there is a distinct concept found inthe present application which does not appear in the prior art. Thisconcept involves the use of a relatively non-stretchable fabric memberformed in place, as by braiding, and providing the only force whichunifies the conduit and creates convolutions between the coils. Inaddition, the present invention provides for the manufacture of acorrugated hose without the use of a hard metal mandrel such asdescribed in the last-mentioned patent.

3,279,502 Patented Oct. 18, 1966 ice It is, therefore, a principalobject of the present in vention to provide a relatively inextensibleflexible conduit which is light, flexible, resistant to collapse and hasa pleasing appearance.

It is a further object of the present invention to provide such aconduit having internal reinforcing coils and outer elastomeric memberswhich are secured to the coils without the use of heat, adhesive,cording, or molding.

It is a further object of the present invention to provide a conduithaving an outer cover formed in place, as by braiding, to createconvolutions between the turns of the reinforcing coil.

To achieve the above and additional objects of the invention, asapparent from reference to the following description, a principal formof the invention contemplates utilizing continuous movement of areinforcing coil through an extruder or crosshead tuber which thusdeposits an outer elastomeric member upon the reinforcing coil. This issomewhat similar to the methods described in United States Patent Nos.2,931,069 and 2,963,749. The covered conduit is then passed through abraiding machine in which the tight braid is formed in place upon theconduit to create the unifying force.

A variation of the above method may consist of manufacturing individualconduits in the manner practiced by applicants assignee in thefirst-mentioned group of patents above. Additional variations includethe use of compressible or crushable mandrels which may be used duringthe processing and later removed, and the addition of outer elastomericmembers around the fabric cover in order to provide a more desirablesurface. Regardless of which of the above methods are used, thenecessity for heat bonding, adhesive bonding, cording, or molding iseliminated, thus providing a product which is relatively inextensibleand yet has the properties of free and unopposed flexing when it isnecessary to form bends in the conduit. The elimination of conventionalbonding means provides improved flexing for such purposes.

The invention is further described in the following specification anddrawings, in which:

FIGURE 1 is an elevational view, partially in section, illustrating amethod of manufacturing the conduit.

FIGURE 2 is an enlarged elevational view, partially in section,illustrating a completed product made in accordance with FIGURE 1. I

FIGURE 3 is a sectional view of an alternative method of manufacturing aconduit in accordance with the present invention.

FIGURE 4 is an elevational view in partial section illustrating avariation of the method illustrated in FIG- URE 3. I

FIGURE 5 is a sectional view illustrating a variation of the method ofFIGURE 3.

FIGURE 6 is a sectional view of a method of manufacturing a modifiedconduit of the present invention.

FIGURE 7 is an elevational view in partial section illustrating afurther step in the manufacture of the conduit of FIGURE 6.

FIGURE 8 is an elevational view, partially in section, of a completedconduit made in accordance with the processes of FIGURES 6 and 7.

FIGURE 9 is an elevational view illustrating a further modified process.

' FIGURE 10 is a sectional view of a conduit resulting from the modifiedprocess of FIGURE 9, taken along lines 1010 of FIGURE 9.

Referring now to FIGURE 1, a preferred method of forming the conduit isillustrated in which a reinforcement having axially spaced turns, suchas a continuous helical reinforcing spring 11, is passed by well-knownmeans through the orifice 12 of an extruder or crosshead tuber 13. Thespring is made of a metal or plastic wire coated with synthetic ornatural rubber, or a thermoplastic material such as vinyl, polyethylene,polypropylene, etc. In the upper portion of the extruder, is a mass ofmaterial such as polyvinyl chloride, polyethylene, polypropylene,rubber, or other extrudable thermoplastic materials, gen-. erallydesignated by reference numeral 14. These materials are referred tothroughout the specification as elastomeric, by which is particularlymeant materials capable of plastic flow, having a high degree of elasticmemory and capable of shaping. Although rubber and thermoplasticmaterials are preferred, certain thermosetting plastics may also providethese properties. This material, which is designated in the-figure as aplastic, is forced through the orifice by means of a driving mechanism15. Further details of the coil advancing mechanism and the extruder arenot illustrated in further detail since these are also old in the art,as described for example in United States Patents Nos. 2,931,069 and2,963,- 749 which relate generally to methods of extruding overreinforcing coils in similar fashion. The passage of the material 14through the extruding die causes the material to form in the shape of anouter layer 16 that continuously covers the coil after it has passedthrough the extruder. From this point the assembly passes through abraider 17 which consists of a rotating ring upon which is mounted anumber of spools 18 and 19 of fibers. These fibers may be nylon, rayon,polyester, cotton,-or other suitable materials.

It should be noted at this point that the passage of the assembly may bein a straight line rather than being formed into a bend as showninFIGURE 1, but this showing is primarily for the purpose of convenience.Although only two spools are illustrated in this drawing, it isunderstood that as many as desired may be used; in fact, the actualnumber to be used will be closer to ten or twelve. The full details ofthe type of braiding machine to be used are not described herein, butmay be found by referring to United States Patent No. 2,257,648 whichillustrates more fully the working of such a mechanism. The braidingmechanism applies a tightly braided cover 22 around the previouslyassembled coil and outer elastomeric tubing; by setting the braidingmechanism for a theoretical diameter which is less than the diameter ofthe coil, it is possible to create a very tight braid and force thethermoplastic material deeply between the adjacent turns of thereinforcing coil, thus creating corrugations. As an example of therelationship of the various members, the coil 11 has an internaldiameter of 1.250 inch and an external diameter of 1.382 inch; the outerlayer 16 before braiding will have the same internal diameter as theexternal diameter of the coil; While the braider is set to provide atheoretical diameter of about 0.25 inch; by theoretical diameter ismeant the diameter which would be obtained from the braiding mechanismif a tube were braided by itself instead of upon the coil and layerassembly. Of course, the braided cover never reaches this theoreticaldiameter because of the opposing force provided by the coil 11, but theresultant cover has a high degree of radial force upon the coil. Theelements of the braid, as shown in the drawing, are applied atapproximately 90 degrees to the axis of the conduit as it passes throughthe machine, varying from this angle by no more than degrees. Thisangular relationship is highly important in order to obtain the maximumradial pressure referred to above. After the braiding step, the conduitis severed to length by a cutter 31.

Because of the unifying force provided by the braid on the outersurface, it is possible to create a completely unified assembly withoutthe need for heat, cording, adhesive, or molding. It has been noted,however, that the pressure of the outer cover 16 on the coated surfaceof the coil 11 may create a slight bond because of the cold flow of thecontacting thermoplastic materials. It should be further noted that theeffect produced herein cannot be obtained by knitting, weaving, or anyother textile processing since only braiding will provide the necessaryradial force. The braided cover is actually formed in place over theelastomeric tube and the re-. sultant assembly is thus different fromthose having cover-s which are pre-formed. The tightness of the braidand depth of the corrugations may be controlled by the setting of themechanism. Itis possible to braid the cover fairly loosely and byapplication of heat (such as steam) the cover may be later shrunk toachieve the tight cover desired. 7

FIGURE 2 illustrates a completed segment of conduit 20 manufactured inaccordance with the process just described. As can be seen, thereinforcing coil 11 has a coated thermoplastic surface 21 which issimilar to the materialused in the outer, thermoplastic layer 16. Theouter braided cover designated as 22 has created the locking force andthe deep corrugations shown therein.

In lieu of the extrusion step illustrated in FIGURE ,1, a non-continuousmethod of forming the coil and elastomeric ,cover may be obtained byfollowing the teachings of the above-mentioned Patent No. 2,822,857. inwhich the elastomeric cover is snapped over the reinforcement. Theresultant assembly is then passed through the braiding mechanism as inFIGURE 1 in orderv to obtain a finished product which, however, will bein the form of a shorter individual unit instead of a long con-1 tinousunit as producedby FIGURE 1.

. FIGURE 3 illustrates a modified form of the invention in which thecoil 23 of desired length is placed upon a compressible mandrel 24.;This mandrel, which iscircular in cross section, is approximately thesame length as that of the coil, which is placed loosely upon saidmandrel as shown. The mandrelm-ay be made of any soft thermoplasticmaterials such as those discussed above, or as shown in the figure, itmay be made of rubber. If desired, the central portion of said mandrelmaybe comparatively rigid and made of jointed segments of a metal suchas aluminum, and surrounded by the soft material. As a furthermodification, the mandrel may be. made of a hollow tube of the softmaterial, rather, than a solid one. In each case, there is provided amandrel which is compressible and yet sufiiciently rigid to retain thecoil. The entire assembly; is now placed within a vacuum box 25 morefully. described in the aforesaid Patent No. 2,822,857 and by means ofthe process described therein an assembled unit is formed by placing anouter tubular member ,26 within the vacuum box and collapsing it uponthe coil and mandrel. Although the member 26 is illustrated as beingrubber, it may, be made, of any of the other materials described above.In lieu of forming a coil with a soft mandrel in a vacuum box,

the mandrel may be fed through the previously de-.

scribed crosshead as shown in FIGURE 4, the outer. cover 16 formedexactly as before and placed about the mandrel and coil. From this pointit is passed through the braider as in FIGURE 1 and the outer braidedcover is locked on as before. It is now only necessary to re-. move thecompressed mandrel by pulling it from the completed conduit 20; this isillustrated in FIGURE 4 as a manual procedure, but may also be done byautomatic machinery. It is also possible to cut the mandrel andsurrounding conduit to a desired length prior to removal of the mandrel.

The compressible mandrel has additional advantages than those justdescribed. For example, the reinforcement with axially spaced turns neednot be a helical coil, but may consist of a series of individualcircular members such as designated by reference numeral 33 in FIG- URE5. These members are placed upon the mandrel 24 in axially spacedrelationship, having a diameter sufiicient to very slightly compress themandrel and retain the axial relationship. The mandrel and reinforcementare further processed as in FIGURE 3, in which an outer tube is snappedon, and subsequently passed through the tuber or extruder as in FIGURE4.

The compressible mandrel described above will provide slightly morestiffness and resistance to the braiding forces, which in some instancesis desirable. It thereby serves as another means for controlling radialforces applied during the process.

FIGURE 6 illustrates a modified form of the invention employingbasically the vacuum box method previously referred to, in which thetubular cover is placed within the vacuum box 25, the vacuum applied toexpand the tubular member to the position shown, and the helicalreinforcing coil placed within the cover. A pair of cylindrical tips 27are then inserted within the coil as shown; these tips preferablyconsist of the same material as the tubular member 26, are hollow, andhave central boss portions 28 and reduced end portions 29 and 30. Theportions 30 are inserted within the coil, thus permitting the remainingportions of the tip to extend radially outwardly thereof. When thevacuum is released, the cover 26 is collapsed inwardly to tightlysurround the coil and the tips. The portion of the cover material 26which extends beyond the shoulder 38 is excess and is trimmed away, in amanner which is conventional in the art of 'hose making; this excessmaterial having served its function of providing a vacuum box seal. Theentire assembly is then passed through the braiding mechanism and atight cover braided over the entire assembly of conduit and tips, asshown in FIGURE 7. The resultant product may then be severed by cuttingmidway of the tips by means of a conventional cutter 31 as shown. Theentire surface may then be coated with rubber or plastic material bymeans of a spray 34 as shown; or alternatively, by dipping, by snappingon another tube as in FIGURE 6, or by passing through an extruder as inFIGURE 1. The resultant product 35 is illustrated in greater detail inFIGURE 8 and consists of the reinforcing coil 23, the outer tubularmember 26, the outer braided cover 22, one-half the original tip section27 in which the portion 30 is within the coil and one-half of theoriginal boss portion '28 extends outwardly thereof, and the outercoating 32. This product has particular utility for automotive radiatorcoolants in which an outer protective cover is desirable; for such usethe materials are illustrated as being of rubber, but they may be madeof the plastic materials referred to above. In lieu of providing anouter cover only, it may be desirable to place an inner coating withinthe tube as well. This may be accomplished by the process illustrated inFIGURE 9, in which the conduit 35 is shown supported by a holder 36 andis dipped into a tank 37 containing a suitable elastomeric materialwhich then coats both inner and outer surfaces. The resultant producthas coatings or coverings 39 on both surfaces, as illustrated in FIGURE10.

The present invention provides a highly useful, relatively inextensibleconduit, in which the bonding is accomplished Without the use ofconventional molding, heat, ad-

hesives, or cording. The braided outer surface provides a high degree ofradial force which locks the entire assembly together, and is the onlyforce providing this function.

While the present invention has been described above by means ofspecific embodiments, it is understood that these are merely exemplaryand in no way intended to limit the scope of the invention claimedherein.

I claim:

1. A flexible inextensible externally corrugated conduit consisting ofan internal reinforcement having axially spaced turns, an elastomericmember embracing said rein forcement and a braided fabric coverembracing said member and exerting a radially inward force against saidreinforcement and which is the sole force unifying the resultingassembly, said member and cover partially surrounding said turns andextending inwardly therebetween.

2. The conduit of claim 1 in which said cover consists of at least twoelements applied at an angle of between and degrees to the axis of theconduit.

3. The conduit of claim 1 in which said reinforcement is a helical coil.

4. The conduit of claim 1 in which said reinforcement comprises aplurality of individual annular rings.

5. A flexible inextensible externally corrugated conduit consisting ofan internal reinforcement, an elastomeric member embracing saidreinforcement to form a first assembly, tip sections located at the endsof said assembly, and a braided fabric cover embracing said member andtip sections and exerting a radially inward force to hold said tipsections within said member and which is the sole force unifying saidreinforcement, member, and tip sections.

6. The conduit of claim 5 having a coating of elastomeric material onthe interior surface thereof.

7. The conduit of claim 5 having a coating of elastomeric material oversaid cover.

References Cited by the Examiner UNITED STATES PATENTS 314,440 3/1885Eames 138122 X 1,345,971 7/1920 Star 138-121 X 2,430,081 11/ 1947 Robertet a1 138122 X 2,836,181 5/1958 Tapp. 2,89 8,942 8/ 1959 Rothermel 138-122 2,917,568 12/1959 Moorman et al. 138-122 X 3,007,497 11/ 1961Shobert 138-125 FOREIGN PATENTS 742,477 12/ 1932 France.

349,965 5/ 1931 Great Britain.

426,694 4/ 1935 Great Britain.

740,732 11/ 1955 Great Britain.

137,293 8/ 1960 Russia.

LAVERNE D. GEIGER, Primary Examiner.

H. K. ARTIS, Examiner,

1.A FLEXIBLE INEXTENSIBLE EXTERNALLY CORRUGATED CONDUIT CONSISTING OF ANINTERNAL REINFORCEMENT HAVING AXIALLY SPACED TURNS, AN ELASTOMERICMEMBER EMBRACING SAID REINFORCEMENT AND A BRAIDED FABRIC COVER EMBRACINGSAID MEMBER AND EXERTING A RADIALLY INWARD FORCE AGAINST SAIDREINFORCEMENT AND WHICH IS THE SOLE FORCE UNIFYING THE RESULTINGASSEMBLY, SAID MEMBER AND COVER PARTIALLY SURROUNDING SAID TURNS ANDEXTENDING INWARDLY THEREBETWEEN.
 5. A FLEXIBLE INEXTENSIBLE EXTERNALLYCORRUGATED CONDUIT CONSISTING OF AN INTERNAL REINFORCEMENT, ANELASTOMERIC MEMBER EMBRACING SAID REINFORCEMENT TO FORM A FIRSTASSEMBLY, TIP SECTIONS LOCATED AT THE ENDS OF SAID ASSEMBLY, AND ABRAIDED FABRIC COVER EMBRACING SAID MEMBER AND TIP SECTIONS AND EXERTINGA RADIALLY INWARD FORCE TO HOLD SAID TIP SECTIONS WITHIN SAID MEMBER ANDWHICH IS THE SOLE FORCE UNIFYING SAID REINFORCEMENT, MEMBER, AND TIPSECTIONS.